Erosion control blocks provide the basic function of preventing the erosion of soil, sand or other material as a result of runoff water, and the like. The cabling of erosion control blocks together is not in and of itself a new concept. Indeed, many types of erosion control blocks are formed with channels therethrough so as to allow cables to be threaded through a matrix of blocks to secure the blocks together and prevent dislodgment of the blocks during heavy water flow thereover. In addition, the cabling of a matrix of blocks together also allows a large mat of blocks to be installed in watershed areas. In this situation, the ends of the cables are tied to respective beams, and the beams are lifted by a crane so that the entire matrix or mat of blocks can be installed simultaneously. This is especially advantageous in underwater installations where manual labor cannot easily be utilized to install each block, one at a time.
Blocks that are of the interlocking type are well known in the art. Each interlocking block includes plural recesses and plural arms so that when neighboring blocks are engaged, they cannot be laterally separated without being lifted vertically. U.S. Pat. No. 5,556,228 by Smith is one such type of interlocking erosion control block. Even when interlocked, the blocks can be cabled together so as to prevent vertical separation of the blocks, as well as to allow the installation of the blocks as a matrix. In many instances, the blocks can be interlocked together as a matrix at the block-forming plant, and cabled together as a mat. The mat can then be lifted by a crane on a truck and transported to the installation site. Many mats can be stacked together on a truck and transported to the installation site. This requires less manual labor than at the installation site. This technique, however, requires the use of an expensive crane at both the manufacturing plant and the installation site.
Many types of erosion control blocks are fabricated in such a manner that they are very difficult to be cabled together once they are interlocked together or otherwise engaged with each other. In some instances, the blocks must be internally threaded on the cable manually, and then lowered into position in engagement with other blocks. This is not only dangerous and clumsy for the workmen, but it is also time consuming. In other instances, when the erosion control blocks are installed, the cables must be inserted into the end of an outer peripheral block of the mat, and threaded through each inner block of the mat. If the cable channels in each block are not aligned, it is difficult to grasp or otherwise manually manipulate the end of the cable to thread it through all the blocks. This is generally due to the closeness with which each block engages each other, thereby leaving very little space therebetween. Even with some erosion control blocks that have vegetation holes therethrough, the blocks are fabricated so that the cable channels are not formed through the holes.
From the foregoing, it can be seen that with many of the presently made blocks, it is difficult to manually install the blocks at the installation site, and thereafter cable them together so as to provide vertical stability thereto. This technique eliminates the need for a crane at both the manufacturing facility and the installation site.
In any type of cabled revetment block system, irrespective of whether the blocks are of the interlocking type or not, it is not infrequent that one or more of the revetment blocks becomes broken during or after installation. When one or more of the revetment blocks of a mat break, the pieces can be carried away by the water, thus compromising the erosion control capabilities of the matrix. With the blocks available in the prior art, it is extremely difficult, if not impossible, to replace individual blocks of a matrix.
From the foregoing, it can be seen that a need exists for a technique for replacing one or more individual revetment blocks in a cabled matrix. Another need exists for a new revetment block design that allows accessibility to the cable(s) so that the cable can be severed, a new block installed, and the cable(s) spliced to maintain the integrity of the revetment block matrix. Yet another need exists for an installation technique where the blocks can be individually installed over the ground, whether the ground be even or sharply contoured, and thereafter cabled together in an easy and efficient manner.